SPLIT HOPKINSON PRESSURE BAR(SHPB) EXPERIMENTS ON DYNAMIC STRENGTH OF WATER-SATURATED SANDSTONE
WANG Bin1，2，LI Xibing1，YIN Tubing1，MA Chunde 1，YIN Zhiqiang1，LI Zhiguo1
(1. School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China； 2. School of Energy and Safety Engineering，Hunan University of Science and Technology，Xiangtan，Hunan 411201，China)
Abstract：Impact compressive experiments on air-dried and water-saturated sandstone samples taken from Kaiyang Phosphate Mine with a constant length-diameter ratio of 0.5 are conducted with the modified f 75 mm split Hopkinson pressure bar(SHPB) apparatus. Compared with the static mechanical results tested by INSTRON material testing machine，the SHBP test results show that stress-strain relation of water-saturated sandstone under impact loads with intermediate strain rate is different from that under static loads；and its dynamic strength is close to that of air-dried sandstone，which is opposite to the decreased strength under static load condition. For air-dried sandstone，its dynamic yield stress under impact loads with intermediate strain rate is similar to its static yield stress. However，for water-saturated sandstone，the dynamic yield stress increases by two times compared with its static yield stress，which indicates that the sensitivity of water-saturated sandstone dynamic strength dependent on strain rate is more notable than that of air-dried sandstone. Water can influence the dynamic damage patterns of sandstone，thus the impact damage of air-dried sandstone becomes more serious than that of water-saturated sandstone. So the water-free viscosity and Stefan effect of water-saturated sandstone should be considered under impact loads with intermediate strain rate.
